Implantable medical devices, such as electrical stimulators, may be used in different therapeutic applications. In some therapy systems, an implantable electrical stimulator delivers electrical therapy to a target tissue site within a patient with the aid of one or more medical leads that include electrodes or with the aid of one or more electrodes on a housing of the electrical stimulator. During a programming session, which may occur during implant of the medical device, during a trial session, or during a follow-up session after the medical device is implanted in the patient, a clinician may generate one or more therapy programs that are selected to provide efficacious therapy to the patient, where each therapy program may define values for a set of therapy parameters. A medical device may deliver therapy to a patient according to one or more stored therapy programs. In the case of electrical stimulation, the therapy parameters may include the configuration of stimulation electrodes used to deliver the electrical stimulation therapy, which may include the subset of electrodes used to deliver stimulation and the polarities of the electrodes.